A plastic bag in a tree. A sweet wrapper at the roadside. A coffee cup in the river reeds. 

These are the sights of childhood in the UK. They are so common that sisters Amy and Ella Meek never gave the rubbish a second glance.

But one day, everything changed. A lesson about the UN's 14th Global GoalThe UN Global Goals are 17 world goals which 193 leaders pledged to achieve by 2030. They include fighting inequality and ending poverty.  - life below water - opened their eyes to the impact of plastic. 

The problem was worse than they had imagined. It was more than a bag in a tree. New images filled their minds. A turtle choking on a plastic fork. The Great Pacific Garbage PatchA collection of marine debris in the North Pacific Ocean covering an area three times the size of France.  in the ocean. 

The sisters decided to act. Aged 10 and 12, they started picking up litter. But for every crisp packet they removed, another one appeared. More action was needed.

The year, 2016, Amy and Ella set up a charity. Kids against Plastic teaches people about the damage caused by plastic.

"From a kid's point of view, it seems that the generation that created this plastic problem aren't taking the action that's needed to remedy it," says Ella.

"We're not waiting for the adults to take the initiative," adds Amy. "If we don't do something right now, by the time we are middle-aged the plastic problem will have spiralled out of control."

In the five years since, Amy and Ella have published a book, spoken at the House of CommonsThe democratically elected house of the UK Parliament. It consists of 650 Members of Parliament.  and made over 1,000 schools "plastic cleverThe charity's Plastic Clever Schools initiative helps schools and pupils raise awareness of pollution and swap problematic plastics for sustainable options. ". 

They are just weeks away from reaching their goal of picking up 100,000 pieces of single-use plastic - one for each sea mammal killedSea mammals are in danger of being trapped in plastic or mistaking it for food and eating it.  every year by plastic pollution. 

Amy and Ella are not the only children who feel adults have let them down. "The fundamental goal of the adults in any society is to protect their young and do everything they can to leave a better world than the one they inherited," wrote Greta Thunberg and other young activists this August. 

"The current generation of adults, and those that came before, are failing at a global scale." 

One survey of British children found that more than half believe adults are not listening to their concerns. Worldwide, 56% of young people think humanity is doomed. 

This summer, a UNICEFA UN agency responsible for providing humanitarian and developmental aid to children worldwide. report concluded that nearly every child on Earth is exposed to at least one environmental hazardEnvironmental or climate hazards include heat waves, cyclones, air pollution and water scarcity. . In Portugal, six young people are taking their government to court to argue that the failure to act on climate change should be defined as cruelty under human rights law.

Amy and Ella do not let the statistics discourage them. "It's so important to recognise that there is hope, because hope is a powerful force," says Amy.  "We don't aim to fill you all with doom and gloom, but to help you all realise that you can be part of this hope." 

No. Adults created this problem, now they are ignoring their responsibility to solve it. It is children, the people who will one day live with the consequences of climate change, that are stepping up to save the world. The adults have failed. 

Yes. Their track record is not good, but adults are beginning to listen to children. The Paris Agreement, signed in 2015 by 197 world leaders, was a major step forward. Now COP26 is a major opportunity for adults to show they care about the future.